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References: <20230605010117.794691-1-utkarsh.h.patel@intel.com> <20230605010117.794691-2-utkarsh.h.patel@intel.com>
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From:   Prashant Malani <pmalani@chromium.org>
Date:   Thu, 15 Jun 2023 10:28:41 -0700
Message-ID: <CACeCKaeVw4UJ8oCj-wmWgf6TCcKYdprqb8Wdu-g2ZC5npgs71g@mail.gmail.com>
Subject: Re: [PATCH 1/2] platform/chrome: cros_ec_typec: Configure Retimer
 cable type
To:     Utkarsh Patel <utkarsh.h.patel@intel.com>
Cc:     linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
        heikki.krogerus@linux.intel.com, bleung@chromium.org
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(Sorry, I've been out on leave so haven't had a chance to look at this earl=
ier)

On Sun, Jun 4, 2023 at 6:00=E2=80=AFPM Utkarsh Patel <utkarsh.h.patel@intel=
.com> wrote:
>
> Connector class driver only configure cable type active or passive.
> With this change it will also configure if the cable type is retimer or
> redriver if required by AP. This details will be provided by Chrome EC
> as a part of cable discover mode VDO.
>
> This change also brings in corresponding EC header updates from the EC
> code base [1].

Please separate this into another patch.

>
> [1]:
> https://chromium.googlesource.com/chromiumos/platform/ec/+/refs/heads/mas=
ter/include/ec_commands.h
>
> Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> Signed-off-by: Utkarsh Patel <utkarsh.h.patel@intel.com>
> ---
>  drivers/platform/chrome/cros_ec_typec.c        | 8 +++++++-
>  include/linux/platform_data/cros_ec_commands.h | 2 ++
>  2 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/c=
hrome/cros_ec_typec.c
> index a673c3342470..9c18b1df64a7 100644
> --- a/drivers/platform/chrome/cros_ec_typec.c
> +++ b/drivers/platform/chrome/cros_ec_typec.c
> @@ -448,6 +448,9 @@ static int cros_typec_enable_tbt(struct cros_typec_da=
ta *typec,
>         if (pd_ctrl->control_flags & USB_PD_CTRL_ACTIVE_CABLE)
>                 data.enter_vdo |=3D TBT_ENTER_MODE_ACTIVE_CABLE;
>
> +       if (pd_ctrl->control_flags & USB_PD_CTRL_RETIMER_CABLE)
> +               data.enter_vdo |=3D TBT_CABLE_RETIMER;
> +
>         if (!port->state.alt) {
>                 port->state.alt =3D port->port_altmode[CROS_EC_ALTMODE_TB=
T];
>                 ret =3D cros_typec_usb_safe_state(port);
> @@ -522,8 +525,11 @@ static int cros_typec_enable_usb4(struct cros_typec_=
data *typec,
>         /* Cable Type */
>         if (pd_ctrl->control_flags & USB_PD_CTRL_OPTICAL_CABLE)
>                 data.eudo |=3D EUDO_CABLE_TYPE_OPTICAL << EUDO_CABLE_TYPE=
_SHIFT;
> -       else if (pd_ctrl->control_flags & USB_PD_CTRL_ACTIVE_CABLE)
> +       else if (pd_ctrl->control_flags & USB_PD_CTRL_RETIMER_CABLE)
>                 data.eudo |=3D EUDO_CABLE_TYPE_RE_TIMER << EUDO_CABLE_TYP=
E_SHIFT;
> +       else if (!(pd_ctrl->control_flags & USB_PD_CTRL_RETIMER_CABLE) &&
> +                 (pd_ctrl->control_flags & USB_PD_CTRL_ACTIVE_CABLE))
> +               data.eudo |=3D EUDO_CABLE_TYPE_RE_DRIVER << EUDO_CABLE_TY=
PE_SHIFT;
>
>         data.active_link_training =3D !!(pd_ctrl->control_flags &
>                                        USB_PD_CTRL_ACTIVE_LINK_UNIDIR);
> diff --git a/include/linux/platform_data/cros_ec_commands.h b/include/lin=
ux/platform_data/cros_ec_commands.h
> index ab721cf13a98..c9aa5495c666 100644
> --- a/include/linux/platform_data/cros_ec_commands.h
> +++ b/include/linux/platform_data/cros_ec_commands.h
> @@ -4963,6 +4963,8 @@ struct ec_response_usb_pd_control_v1 {
>  #define USB_PD_CTRL_TBT_LEGACY_ADAPTER  BIT(2)
>  /* Active Link Uni-Direction */
>  #define USB_PD_CTRL_ACTIVE_LINK_UNIDIR  BIT(3)
> +/* Retimer/Redriver cable */
> +#define USB_PD_CTRL_RETIMER_CABLE BIT(4)

Why are we adding this to this host commands interface? Is this
information not available from the Cable (plug)'s
Identity information? We register all of that in the port driver
already [1], so we should just use that, instead
of changing the host command interface.

Thanks,

[1]  https://elixir.bootlin.com/linux/v6.4-rc6/source/drivers/platform/chro=
me/cros_ec_typec.c#L768